Key Issues

Life-Cycle Emissions Analysis

Nuclear power plants do not emit criteria pollutants or greenhouse gases when they generate electricity. Numerous studies demonstrate that nuclear energy’s life-cycle emissions are comparable to renewable forms of generation, such as wind and hydropower, and far less than those of coal- or natural gas-fired power plants.

Although nuclear power plants do not emit greenhouse gases when generating electricity, certain processes used to build and fuel the plants do. This is true for all energy facilities. Nuclear energy life-cycle emissions include emissions associated with construction of the plant, mining and processing the fuel, routine operation of the plant, disposal of used fuel and other waste byproducts, and decommissioning.

Nuclear Comparable to Renewables

Numerous studies demonstrate that nuclear energy’s life-cycle emissions are comparable to renewable forms of generation, such as wind and hydropower, and far less than those of coal- or natural gas-fired power plants. For example, a University of Wisconsin study (PDF) found that nuclear energy’s life-cycle emissions are 17 metric tons of carbon dioxide-equivalents per gigawatt-hour. Only wind and geothermal sources ranked lower, at 14 and 15 metric tons of carbon dioxide-equivalents per gigawatt-hour, respectively.

University of Wisconsin chart on life-cycle emissions comparisons

In May 2005, British Energy completed a study into the life cycle impacts of generation from its Torness nuclear power station. The assessment covered the entire fuel cycle and included nuclear waste, spent fuel and CO₂ , SO₂ and NO_x emissions.

The total emissions of CO₂ from electricity generated at Torness power station, calculated on a lifecycle basis, are estimated to be just over 5 g/kWh. This compares to emissions of CO₂ from a typical UK coal plant of around 900 g/kWh, based upon the operational stage alone. Typical gas power station CO₂ emissions are around 400 g/kWh.

Technical Report (PDF)
Executive Summary (PDF)

Many nuclear critics have claimed that new nuclear plants would need to use lower ore uranium, which requires more energy to extract, and therefore would have higher emissions. In response, British Energy conducted a follow-up study that showed even with a very low uranium ore grade, CO₂ emissions would remain very small. If Torness used this ore for all its fuel, its emissions would only rise from 5.05 g/kWh to 6.85 g/kWh.

Follow-up report (PDF)

An International Energy Agency (IEA) analysis found that nuclear power’s life-cycle emissions range from 2 to 59 gram-equivalents of carbon dioxide per kilowatt-hour. Only hydropower’s range ranked lower, at 2 to 48 grams of carbon dioxide-equivalents per kilowatt-hour. Nuclear energy’s life-cycle greenhouse gas emissions are lower than wind (7 to 124 grams of carbon dioxide-equivalents) and solar photovoltaic (13 to 731 grams of carbon dioxide-equivalents), according to the agency. The life-cycle emissions from natural gas-fired plants ranged from 389 to 511 grams of carbon dioxide-equivalents per kilowatt-hour.